Ground improvement is the procedure typically defined as using mechanical means to improve poor ground conditions. Ground improvement methods improve the engineering properties of the soil mass which is treated to meet project performance requirements.
Common reasons for ground improvement include:
There are several types of ground improvement. The most adopted methods include:
SURCHARGINGconsists of applying load on the ground surface in excess of that associated with the long-term development conditions to accelerate consolidation. Once sufficient consolidation has been achieved the pre-load can be removed and the project construction can commence.
WICK DRAINSPrefabricated vertical drains (PVDs), also known as wick drains, are used to accelerate the consolidation process by reducing the distance of the drainage paths. They are made of a plastic core encased by a geotextile. The spacing and the size of PVDs depends on the properties of the hydraulic soil and the desired consolidation time of the project. This method is usually combined with preloading of the soil. The temporary load initially increases pore water pressure and then drain flow occurs. Pore water will flow laterally to the nearest drain following a shorter path reducing the preloading time.
LIME STABILIZATIONis a ground improvement technique that involves adding lime to the soil to improve its properties. Stabilization is achieved when the proper amount of lime is added to a reactive soil and exchange of ions occurs. Clayey soils of moderate to high plasticity are suitable for implementing this technique. Sufficient curing time has to be provided, as the rate of strength gain is rapid during initial stages. The gain in strength is also affected by the temperature at which curing takes place. High temperature during curing leads to enhanced strength. Lime stabilization technique is usually used in road construction to improve sub-bases and subgrades and for railroad and airport construction.
DEEP SOIL MIXINGis a ground improvement technique that enhances the characteristics of weak soils by mechanically mixing them with cementitious binder slurry to the target depth. This method produces individual soil-cement (soilcrete) columns, rows of overlapping columns or total mass stabilization increasing soil’s strength and stiffness.
JET GROUTINGis a ground improvement technique that uses high-pressure jets which release cement grout into a borehole to form cemented soils. The grout is injected at high velocity and breaks up the soil structure. The soil particles mix with the grout creating a homogenous mixture. Using this technique, soilcrete panels, full columns, or partial columns with specific strength and permeability are constructed. Jet grouting is used for the underpinning of structures, sealing the bottom of planned excavations, tunneling construction, and consolidating soft foundation soils. Grouting creates large, cemented material columns in limited working spaces and with no soil material disposal.
DYNAMIC COMPACTIONis a ground improvement technique that uses a drop weight to densify loose soils. Soil densification is carried out by the repeated, controlled impact of a heavy weight (10-40 tons) on the ground surface. Vibrations are generated for a considerable lateral distance. With this method, bearing capacity is improved, settlements are reduced and liquefaction potential is diminished.
RIGID INCLUSIONare a ground improvement method using high deformation modulus columns constructed through compressible soils to reduce settlement and increase bearing capacity.
Ground improvement efficiency depends on the stiffness relationship between the soil and the columns. The load from the structure is distributed to the soil and columns via a load transfer platform or rigid foundation. Its common uses are:
STONE COLUMNSThis technique involves constructing load-bearing columns made from gravel or crushed stones using a vibrator to reinforce all soils in the treatment zone and densify surrounding granular soils. Common uses include:
At GEOCONSOL, we deliver a tailored suite of the following services to accommodate project geology, complexity, diverse design solutions, and safety requirements.
GEOCONSOL, has certified resources to provide the above services.
At GEOCONSOL, we deliver a tailored suite of the following services to accommodate project geology, complexity, diverse design solutions, and safety requirements.
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